Humans have been opening shelled nuts since...well, since we used rocks. Most people I know have moved beyond bashing their food with heavy objects to using some sort of nutcracker. I have a set that my parents owned, and although the nutcrackers and picks are ancient, they work well. As long as you've got the grip strength.
Some people don't have quite that much power, so a better engineered nutcracker could be a good idea.
The Drosselmeyer nutcracker ($39.95), besides being attractive, also makes the job easier—something to do with leverage, I'm sure. It easily handled every type of nut I threw into it, from hazelnuts to Brazil nuts to walnuts. The largest of the walnuts didn't fit entirely inside the maw of the cracker, but it got the job done, anyway.
I put this cracker out at Christmas, along with a bowl of nuts, and I got plenty of unsolicited comments about how well the nutcracker was made and how easy it was to use.
I'll admit that $40 is a bit pricey for something that has a single function, but given the fact that I've been using the same nutcrackers my parents owned 50+ years ago, I imagine this would last quite some time as well.
Disclaimer: Testing samples were provided to Serious Eats.